Tubing anchor



Feb. 24, 1959 Filed Oct. 17. 19

J. R. BAKER ET AL TUBING ANCHOR 3 Sheets-Sheet 1 Feb. 24, 1959 Filedoct. 17,l 1955 J. R. BAKER ET Al.

TUBING ANCHOR 3 Sheets-Sheet 2 KNK INVENTORS.

Feb. 24, 1959 J. R. BAKER x-:TAL 2,874,784

TUBING ANCHOR Filed Oct. 17. 1955 -3 Sheets-Sheet 3 E 6 ajraif e. @l 2.J 4 w 5MM UnitedStates Patent O TUBING ANCHOR Jolln R. Baker, Pasadena,and Earnest H. Clark, Jr., Downey, Calif., assignors to Baker Gil Tools,Inc., Los Angeles, Calif., :a corporation of California ApplicationOctober 17, 1955, Serial No. 540,732

-15 Claims. (Cl. 166-212) hydraulically actuatable retrievable apparatusfor securingva tubular string to a well casing, or the like, againstupward movement therein, in which the hydraulic pressure developed as aresultl of runningthe apparatus through the lluid in the well casing isprevented from expanding the slips or gripping members of the apparatusinto engagement with the wall of the well casing. Accordingly, the slipsare not dulled during lowering of the apparatus in the well casing andare eiective to anchor the apparatus to the casing against upwardmovement therein, when the anchoring location in the casing hasbeen-reached, and to withstand high pressures tending to force theapparatus up the well casing.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of a formin which it'may be embodied. This form is ,shown in the drawingsaccompanying and forming part of the present specication. It will now bedescribed in detail, for the purpose of illustrating -the generalprinciples of the invention; but it is to be understood that suchdetailed description is not to be taken in a limiting sense, since thescope of the invention is best dened by the appended claims.

Referring to the drawings:

Fig. l is a longitudinal section through a tubing anchor, with its partsin retracted position;

Fig. 2 is a view similar to Fig. l, on an enlarged scale, disclosing theapparatus anchored against the well .casm8;

Fig. 3 is an enlarged cross-section taken along the line 3--3 on Fig. l;

Fig. `4 is an enlarged fragmentary longitudinal section through thelatching portion of the apparatus, with the parts disposed in theposition shown in Fig. l;

Fig. 5 is a view similar to Fig. 4, with the parts disposed in theposition illustrated in Fig. 2;

Fig. 6` is a view similar to Fig. l, illustrating the apparatus 'beingelevated in the Well casing;

Fig. 7 is an enlarged fragmentary section taken along the line 7-7 onFig. 6;

Fig. 8 is an enlarged fragmentary section taken along the line 8--8 onFig. 6.

The tubing anchor A disclosed in the drawings is adapted to be securedto a well casing B, well liner, or the like, against upward movementtherein, despite the presence of comparatively high pressure therebelow.The apparatus A is lowered in the well casing by means of a tubularstring C, which can be formed of tubing or drill v pipe. The lower endof the apparatus can be secured to a lower tool D, such as a retrievablepacker, that is adapted to be anchored in packed-off condition inthewell casing against downward movement therewithin. Inasmuch as theretrievable packer D forms no part of fi Ice 2,874,784

f 2 the present invention, only'its upper tubular body portion isdisclosed.

The tubing anchor A includes a body 10 consistmg of an upper tubularbody section 11, the lower end of which n is threadedly secured withinla lower body section 12. This latter section, in turn, has a lowerthreaded pin 13 adapted to be threadedly secured to the upper box 'end14 of the body D of the lower tool. Spaced about the body of the toolare a plurality of slips 15, or corresponding gripping members, whichcan shift laterally between retracted and expanded positions. The lowerends of the slips are disposed within radial slots 16 in the upperportion of the lower body section 12, the slips being guided in theirradial movement by pins 17 `secured to their lower portions, each pinprojecting in opposite directions from the side faces of a slip and intoopposed grooves 18 on opposite sides of the body slot 16. Thedisposition of the pins into these grooves 18 permits the slips 15 toslide radially relative to the body section 12, while preventing anysubstantial longitudinal movement of the slips with respect to this bodysection.

The slips 15 extend upwardly from the lower body section, being receivedwithin circumferentially spaced grooves 19 provided in an expandermember 20. The

base 21 Vof each groove is inclined in a downward and inward direction,coacting with a companion inclined ,slidable connection between theexpander and the slips.

The expander l20 is shifted Adownwardly within the slips 15, to forcethe slips into anchoring engagement with the wall of the well casing, byvirtue of uid under pressure Within the tubular string C and the body 10of the tool. The fluid under pressure will pass through. upper and lowersets of ports 26, 27 through the upper body section 11 into a cylinderspace 28 defined between an upper.

annular piston`29 integral with and extending outwardly from the bodysection above the ports 26 and the upper portion 30 of the expanderwhich may be considered to be the head of the hydraulic cylinder, andalso dened between the periphery of the body 11 and a cylinder sleeve orhousing 31, the lower end of which is threadedly securedY to theexpander head 30, and which extends upwardly along and above the piston29 to a substantial extent.

The upper end of the cylinder sleeve 31 is threadedly secured onto ahead 32 that is slidable along a tubular mandrel 33, the lower portion34 of which is telescoped over the upper body section 11 above thepiston 29, and the upper end of which is formed as a threaded pin 35threadedly secured to aI coupling 36 that is, in turn, threaded onto thelower end of the tubular string C. It may be desirable to transmit theturning effort of the tubular string C and mandrel 33 to the lower toolD secured to the lower. body section 12. For that purpose, the mandrel33 may be provided with a longitudinally extending groove or keyway 37receiving a key or pin 33 secured to the upper head 32. Turning eifortimposed on the mandrel 33 will be transmitted through the key 38 to theupper head 32,and from the latter, through the cylinder sleeve 31,expander 20 and slips 15 to the lower body section 12, from where theturning motion is transferred to the lower packer body D.

Fluid is prevented from leaking from the cylinderV spacey Patented Feb.24, 1959 gsvgrefi' ably" andse'alingly engaging the inner wall ofthe`c'ylilldel:`

sleeve,3 1. Fluid is prevented from leakingmina down-A ward directionbetween the cylinder. head 30 end upper body section `11 by providing aninternal seal ring 42, such as' a rubber orA rubber-like 0 ring, inan'internal groove 43'in the cylinder head, whichslidably seals againstthe periphery of the upper bodyrsection. A thread seal 44 may beprovided in a groove `45 in the cylinder head 30, engaging the wall ofthe cylinder sleeve'31' to prevent leakage through theV threadedconnectioirbetween the sleeve and the cylinde'rhead or expander 20.Likewise; fluid is prevented from passing between the `rriandrelr.33andthe body .portion111 .aboyev the piston 29 lby a suit-v ablelsealring 46, such asa rubberor rubber-like O ring A located in anvinternal'groove 47 in" the lower head 34 of the` mandrehwhich slidablyandisealingly engages the periphery ofthe body 11a above thepiston. v

In'the operation ofv the'fapparatusl A so far described, it is yrun inthe well casingB by the tubular string C, with its lower body section 12attached to the body D of the lower tool, and withits expander 20disposed in an upward position withrespect to the slips 15, which areheld ina retracted position. As assurance against the dropping of theexpander 20 by gravity along the slips 15, a helical-compression spring50 may. be disposed in the annular space 51 between the mandrel 33 andthe cylinder sleeve '31, withv its lower endV bearing against the lowermandrel head 34 and its upper endagainst the upper cylinde'rhead 3 2.V`This spring will tend to maintain the expander 20 in 'itselevated'position. The apparatus is lowered through the uid in the wellcasing until the location is reached at which it is to be anchored tothe latter. When such location is reached, the tubing string C issuitably manipulated to anchor the lower packer D in packedot conditionwithin the well casing. Thereafter, pressure mayY be imposed onthe uidin the tubular string C, ma'ndrel 33 andbody 10 of the tool, such uidunder pressure passing through the ports 26, 27 and into the cylinderspace 28, to act in a downward direction on the cylinder head 30 andshift the expander 20 downwardly within the slips 15, expanding thelatter outwardlyinto anchoring engagement withthe wallof the wellcasing.

It is to be noted thatfthe wickers or teeth 23 on the slips 15 face inanupwarddirection, so as to anchor the slips -to the casing aganstupwardmovement vwith respect thereto. Upward movement of the lower packer D,as a result of pressure in the casing .therebelow, is preventedin viewof the anchoring of the slips against the well casing. Such pressure isalso present within the body 10, and is acting in a downward directionon the expanderhead 30 to hold the expander 20 wedged behind'the slips15, preventing their retraction from the well casing.

When the apparatus- A is to be released from the well casing B, thepressure is relieved and an upward pull taken on the tubular string C,which will be transmitted to the mandrel 33, shifting the latterupwardly alongv the body 10 and the cylinder sleeve 31. The mandrel isprovided with an upwardly facingshoulder 52, which will engage the lowerend of the upper cylinder headA 32,-\

whereupon further upward movement of the mandrel 33 istransmittedthrough the head 32 and cylinderk sleeve 31 to the expander20; to raise the latter with respect to the `slips 1S and effect ashifting of the slips to their retracted position. During upwardmovement of the apparatus A in the well casing B, the expander 20 willbe heldin its upper position relativeto theslips 15, to insure thatthelatter will remain in their retracted position. If it is desired toagainanchor the slips to the casing, it is merely necessary torelowenthe mandrel 33 valong the body 1( t o reengage therilownhead 314withl the .pistonm 29, and then provide pressure in the tubular stringC,

relative to the body 10 against the forceof the spring 50,

to engage the slips 15 with the wall of the well casing. With the slipsengaging the wall of the well casing, downward movement of the apparatuswill slide the wickers 23 along the casing, which might result in theirbeing dulledwhen the location in the4 well casing is reached at whichthe apparatus is to be anchored. Accordingly, the slips 15 may be unableto withstand any substantial upwardly directed forces or pressureimposed thereon.

The present invention seeks to overcome the aforenoted ditiiculty bypreventing the expander 20 from being shifted downwardly within theslips 15 yuntil s uch action is desired. A latching device isincorporated between the expander 20 and thev body 10 of the toch-whichis effective to hold the expander inan upward position and which must besubjected to substantial pressures bel fore its release can occur. Thelatching device consistsy of a split, inherently contractile ringy 53placed around' the body 10 between the expander 20 and the piston 29.This ring'has a lower surface 5 4 inclined at a substantial angle'in adownwardv and outward direction, and this holding surface 54 isadaptedto engagea companion holding surface or shoulder 55 provided onthe,l body,V sectionl 11, 'preferably immediately below the upperlset-of ports 26. @The ring S3 is contained within an internalv groove 56formed between a coupling or retainer ring 57 and the upper end of theexpander or cylinder head 30. Thus, Vthe coupling ring 57 is made of twohalves, with its periphery 58 engaging the inner wall of the cylinf dersleeve31. This ring has a lower, inwardly directed flange 59 receivedwithin an external groovev60 in the cylinder head, and an upwardinwardly directed ilange 61 spaced abovethe upper end of the cylinderhead 30 and also extending across the upper end of the latch ring 53.

The intermediate web portion 62 of the coupling ring be- At this time,the expander 20 is in its uppermost position;`

within the slip/s `.15, .with the upperVV end of the vcoupling ring`57disposed adjacent the body piston 29. The inherent, contractileforce ofthe latch ring 53 and the angle of inclinationvof the body shoulder 55are such as to require a substantial downward force by the upper flange61 on the latch ring to expand the ring outwardly free of the holdingshoulder 55. As an example, the force required to free the latch yringfrom the shoulder may correspond to a pressure differential of 250 to350 p. s. i. within the annular cylinder space 28.

During lowering of the apparatus in the well casing,' pressuredifferential will be developed in the body 10, but the total force ofsuch pressure acting in the cylinder space 28 Vin a downward directionon the expander 20 will neverreach the unit pressure that is necessaryto release the latch ring 53 from the holding shoulder 55. The downwardforce of the pressure von thehead 30 will cause 'the'upper ring flange61 to engage the ring mentv withthe wall' of the well casing, the lowerpacker H D is set and suicient pressure differential is developed Withinthe packer body to overcome the holding force of the latch ring 53. Suchpressure will act in a downward direction on the cylinder head 30, beingexerted through the upper flange 61 on the ring 53. Because of theinclined coaction between the lower end 54 ofthe ring and shoulder 55,the pressure will eventually cause the ring 53 to be expanded outwardlyot the shoulder 55, whereupon the cylinder 31, 30 is shifted downwardlyrelative to the body 10, to shift the expander within the slips andexpand the latter outwardly into anchoring engagement with the wall ofthe well casing B. During downward movement of the cylinder 30, 31 thering 53 will also slide downwardly along the body 11.

It is preferred that the body have a relatively steep tapered periphery70 that inclines in a downward and inward direction from the holdingshoulder 55 and along which a companion tapered surface 71 of the ring53 can slide, to permit the ring to retract to some extent. The coactionbetween this relatively steep body surface 70 andthe ring surface 71will then cause the ring 53 to support the body 10 of the tool, and theapparatus D secured therebelow from the expander and the anchored slips15, and will prevent the force of gravity, or

other relatively light forces, as well as the force of theV compressionspring 50, from inadvertently shifting the parts back to a retractedposition, in the event the pressure within the body 10 of the tool isrelieved, or is reduced to any substantial extent.

When it is desired to retract the slips 15 from the well casing, thepressure is relieved and an upward pull is taken on the tubing string Cand mandrel 33. The man-v drel shoulder 52 moves upwardly against theforce of the compression spring 51, which exerts a comparatively lightforce, until the mandrel shoulder engages the upper cylinder head 32. Anupward pull can now be taken on the cylinder 31 and the expander 20, toshift the latter upwardly relative to the slips 15 and the body 10 ofthe tool. The latch ring 53 will not offer very great resistance to suchupward movement, in view of the relatively steep taper or inclination ofthe coacting surfaces 71, 70 on the ring 53 and the body 10. When theexpander 20 has been shifted upwardly to its fullest extent, the slips s15 will be completely retracted and the latch ring 53 can again snapback into its position above the holdingl shoulder 55, to again precludeinadvertent downward movement of the expander 20 within the slips 15.The apparatus can now be elevated to a new location in the well casingor removed entirely therefrom; or, if desired, it can be lowered toanother setting position within the well casing. During such loweringmovement, any fluid pressure differential within the body 10 of the toolcannot eiect a downward shifting of the expander 20 within the slips 15.

It is to be noted that longitudinally spaced sets of ports ment of thecylinder 31, 30 along the body 10, prevent-` ing relative upwardmovement of the cylinder along the body. Any such particles can beforced out of thecylinder space 28 through the upper sets of ports 26when the cylinder 31, expander 20 and latch Vring 53 are elevated alongthe body to effect reshifting of the slips to their retracted position.The upper set of ports`26 precludes theV presence of any dead pockets orspaces intoY which sand particles or the like can pack.

It is, accordingly, apparent that a tubing' anchor-has been providedwhich is actuatable hydraulically to expand the slips into anchoringengagement with the wall of the well casing, and in which hydraulicforces incident to the lowering of the apparatus through the diuid inthe well casing are incapable of anchoring the slips against the wellcasing. Thus, the slips are prevented from being inadvertently expandedagainst the wall of the well casing during descent ofthe apparatus inthe latter, preventing dulling of the teeth or wickers of the slips,andY insuring that they will be in appropriate condition for anchoringthe apparatus to the well casing securely, and with a capability towithstand comparatively high pressure that might be imposed on theanchor A and tending to elevate it in the well casing.

The inventors claim:

1. In a well tool: a body; expander means on said body; slips cooperablewith and shiftable with respect to said expander means for anchoring thetool to the wall of a well casing; uid actuated means for moving saidslips and expander means in one direction relative to each other toshift said` slips to casing anchoring position; said slips having casingengaging wickers facing in the same direction'as said slipsare movablerelative to said expander means; latch means operatively connected tosaid expander means for preventing relative movement between said slipsand said expander means and releasable in response to a predeterminedpressure imposed upon said expander means to permit relative movementbetween said slips and expander means; and means for shifting said fluidactuated means to relatively move said slips and expander means in theopposite direction to reset said latch means.

2. In a well tool: a body; van expander on said body and having anexpander surface inclined downwardly and inwardly; slips engageable withsaid surface and shiftable relative to said expander for anchoring saidtool to the wall of a well casing; uid actuated means for relativelymoving said expander downwardly within said slips to expand said slipsagainst the wall of the well casing; said 'slips having upwardlyfacingwickers on their exterior surfaces; latch means operatively connected tosaid expander for preventing downward movement of said expander relativeto said slips and releasable in response to a predetermined pressureimposed upon said expander to permit downward movement of said expanderrelative to-said slips; and means for elevating said fluid actuatedmeans with respect to said body to reset said latch means in itscondition preventing downward movement of said expander relative to saidslips.

3. In a well tool: a bodyg'an expander on said body and having anexpander surface inclined downwardly and inwardly; slips engageable withsaid surface for anchoring said tool to the wall of a well casing; iluidactuated means for relatively moving said expander downwardly withinsaid slips to expand said slips against the Wall of the well casing;said ,slips having upwardly facing wickers on their exterior surfaces;releasable latch means engageable with said body and expander to preventdownward movement of said expander relative to said slips, said latchmeans being releasable in response to a predetermined fluid pressureimposed on said expander and urging it downwardly of said body; andmeans for elevating said lluid actuated means with respect to said bodyto reset said latch means in its condition preventing downward movementof said expander relative to said slips.

4. In a well tool: a tubular body; an expander slidable longitudinallyon said body and having an expander surface inclined downwardly andinwardly; slips carried by said body and coacting with said expander tobe shifted outwardly into anchoring engagement with the wall of the wellcasing; means responsive to fluid pressure in said body for shiftingsaid expander downwardly of said body to expand said slips outwardly;latch means engageable with said body and shifting means and releasablein response to a predetermined force exerted on said latch means by saidshifting means for resisting downward movement of said expander alongsaid body; and means for elevating said shifting means with respect tosaid body to re-engage saidrlatch meanswithsaid bodytoY vagain resistdownward movement of saidexpanderalong said body.

5. In a well tool: a tubular body; an expander slidable longitudinallyon said body and. having an expander surface inclined downwardly andinwardly; slips carried by said body and coacting wim said expander tobe shifted outwardly into anchoring engagement with the wall of a wellcasing;rmeans responsive to fluid pressure in said fbody for shiftingsaid expander downwardly of said body to expand said slips outwardly;latch means carried by said shifting means and engageable with said bodyfor resisting downward movement of said expander along said body, saidlatch means being releasable from said body in response to apredetermined force exerted on said latch meansby saidshifting means;and means for elevating said shifting means with respect to `said bodyto re-engage said latch means with said body to again resist downwardmovement of said expander along said body.

6. In a well tool: a tubular body having a piston and a port below saidpiston; an expander slidable longitudinally onv said body below saidpiston and having an expanderV surface inclined downwardly and inwardly;slips coacting with saidexpander to be shifted outwardly into anchoringengagement with the wall of a wellcasing; means coupling said slips tosaid body to prevent relative longitudinal movement between said slipsand body; a cylinder secured to said expander and extending upwardlytherefrom along said piston; lluid under pressure being adaptedto passthrough said port into said cylinder to shift said expander downwardlyof said body to expand said slips outwardly; and latch means carried bysaid cylinde'r and engageable with said body to resist downward movementof said expander along said body, said latch means being releasable inresponse to a predetermined force imposed thereon by said cylinder.

7. In a well tool: a tubular body havinga piston and upper and lowerports below said piston; an expander slidable longitudinally on saidbody below said piston and having an expander surface inclineddownwardly and inwardly; slips carried by said body and coacting withsaid expander to be shifted outwardly into anchoring` engagement'withthe wall of a well casing; a cylinder secured to said expander andextending upwardly therefrom along said piston; fluid under pressure-being adapted to pass through said ports into said cylinderto shiftsaid expander downwardly of said body to expand said slips outwardly;and latch means carried by said cylinder and engageable with said bodyadjacent said upper port to resist downward movement of said expanderalong said body, said latch means being releasable in response to apredetermined force imposed thereon .by said cylinder.

8. In a well tool: a tubular body having a piston and a port below saidpiston; an expander slidable longitudinally on said body below saidpiston and having an` expander surface inclined downwardly and inwardly;slips carried by said body and coactingwith said expander to be shiftedoutwardly into anchoring engagement with the wall of a well casing; acylinder secured to said expander and extending upwardly therefromalongv said piston; fluid under pressure being adapted to pass throughsaid port into said cylinder to shift said expander downwardly of saidbody to expand said slips outwardly; and a split, inherentlycontractible latch ring carried by said cylinder and engageable with anupwardly facing shoulder on said l 9. In a well tool: a tubular bodyhaving a piston and A upper and lower ports below said piston; anexpander slidable longitudinally on said body below said piston andhaving an expander surface inclined downwardlyv and inwardly; slipscarried by said body'and coacting with said expander to be shiftedvoutwardly into anchoring engagement withthe walljof avwell casing; acylinder securedl to saidrexpander and,e xtending upwardly therefromalong -a port below said piston; an expander slidable longitudinally onsaid body below said piston and having an expander surface inclineddownwardly and inwardly; slips carried bysaid body and coacting withsaid expander to be shifted outwardly into anchoring engagement with the,wall ofa well casing; a cylinder secured to said expander and extendingupwardly therefrom along said piston; fluid under pressure lbeingadapted to pass through said port into said cylinder to shift saidexpander downwardly of said body to expand said slips outwardly; and asplit, inherently contractible latch ring carried by said cylinder andengageable with an upwardly facing shoulder on said body lto resistdownward movement of said expander along said body, said latch ringbeing releasable from said shoulder in response to a predetermineddownward force imposed thereon by said cylinder; said body having adownwardly converging surface engaged by said latch ring upon itsrelease from said shoulder to resist upward movement of said expanderalong said body.

' 1l. In a well tool: a tubular body having a piston and a port belowsaid piston; an expander slidable longitudinally on said body below saidpiston and having an expander surface inclined downwardly and inwardly;slips carried by said body coactingwith said expander to be shiftedoutwardly into anchoring engagement with the wall of a well casing; acylinder secured to said expander and extending upwardly therefrom alongsaid piston; lluid under pressure being adapted to pass through saidport into said cylinder to shift said expander downwardly of said bodyto expand said slips outwardly; latch means carried by said cylinder andengageable with said body to Aresist downward movement of said expanderalong said body, said latch means being releasable in response to apredetermined force imposed thereon by said cylinder; and a mandreltelescoped over said body above said piston and engageable with saidcylinder to elevate said expander along said body.

l2. In a well tool: a tubular body having a piston and a port below saidpiston; an expander slidable longitudinally on said body below saidpiston and having an expander surface inclined downwardly and inwardly;slips v response to a predetermined force imposed thereon` by saidcylinder; a mandrel telescoped over said body above said piston andengageable with said cylinder to elevate saidexpander along said body;and spring means between` said mandrel and cylindery tending to elevatesaid cylinder 'and expander with respect to said mandrel and body.

13. In a Well tool: a tubular body having apistonand a port below. saidpiston; an expander slidable longitudinally on said. body below saidpiston and having an ex-I pander surfaceinclined downwardly andinwardly; slips carried -by said body and coacting with said expander tobe shifted outwardly into anchoring engagement with the wall of a wellcasing; a cylinder secured to said expander and extending upwardlytherefrom along said piston; fluid under pressure being adapted to passthrough said port into said cylinder to shift said expander'downwardlyof said body to expand said slips outwardly; a split, inherentlycontractible latch ring carried by said cylinder and engageable with anupwardly facing shoulder on said body to resist downward movement ofsaid expander along said body, said latch ring being releasable fromsaid shoulder in response to a predetermined downward force imposedthereon Iby said cylinder; and a tubular mandrel telescoped over saidbody above said piston and engageable with said cylinder to elevate saidcylinder and expander with respect to said body.

14. In a well tool: la tubular body having a piston and a port -belowsaid piston; an expander slidable longitudinally on said body below saidpiston and having an expander surface inclined downwardly and inwardly;slips carried by said body and coacting with said expander to be shiftedoutwardly into anchoring engagement' with the wall of a well casing; acylinder secured to said expander and extending upwardly therefrom alongsaid piston; uid under pressure being adapted to pass through said portinto said cylinder to shift said expander downwardly of said body toexpand said slips outwardly; and a split, inherently contractible latchring carried by said cylinder and engageable with an upwardly facingshoulder on said body, said latch ring being releasable from saidshoulder in response to a predetermined downward force imposed thereonby said cylinder; said body having a downwardly converging surfaceengaged by said latch' ring upon its release from said shoulder toresist upward movement of said expander along said body; and a tubularmandrel telescoped over said body above said piston and engageable withsaid cylinder to elevate said cylinder and expander along said body torelocate said latch ring in a position engaging said body shoulder.

15. In a well tool: a tubular body having a piston and a port below saidpiston; an expander slidable longitudinally on said body below saidpiston and having an expander surface inclined downwardly and inwardly;slips carried by said body and coacting with said expander to be shiftedoutwardly into anchoring engagement with the wall of a well casing; acylinder secured to said expander and extending upwardly therefrom alongsaid piston; iluid under pressure being adapted to pass through saidport into said cylinder to shift said expander downwardly of said bodyto expand said slips outwardly; latch means carried by said cylinder andengageable with said body to resist downward movement of said expanderalong said body, said latch means being releasable in response to apredetermined force imposed thereon by said cylinder; and means forelevating said cylinder along said body to re-engage said latch meanswith said body to again resist downward movement of said expander alongsaid body.

References Cited in the le of this patent UNITED STATES PATENTS2,435,899 Page Feb. 10, 1948 2,609,879 Webber Sept. 9, 1952 2,735,497Brumleu et al Feb. 21, 1956 2,737,247 Baker et al Mar. 6, 1956

